LATEST: Aspiring rapper KEVIN FEDERLINE is seeking sole custody of his two children with BRITNEY SPEARS, because he hasn't known the location of the young boys since the singer filed for divorce. Federline has been travelling North America promoting his debut album PLAYING WITH FIRE since appearing at the Annual West Hollywood Carnival with Spears last week (31OCT06), the day he launched the disc. Meanwhile, Spears has spent the past week in New York City - appearing on the LATE SHOW WITH DAVID LETTERMAN on Monday (06NOV06); shopping, dining and ice-skating with former manager LARRY RUDOLPH on Tuesday (07NOV06); and spending Wednesday (08NOV06) in a recording studio - without either of her children. Spears filed for divorce on Tuesday, seeking custody of the couple's two young sons SEAN PRESTON, 14 months; and JAYDEN JAMES, two months. Federline filed a response on Wednesday, also seeking sole custody of the kids. MICHAEL SANDS, spokesman for Federline's lawyer MARK KAPLAN, says the former dancer is seeking custody because his estranged wife is keeping their children's location a secret from him. Sands tells the New York Post, "He's on a bus to Baltimore and doesn't know where the kids are. "Perhaps you understand now why he's asking for full custody."